I am using CentOS GNOME 7.x. (Not sure how to determine the exact version.) I right-click on items in various places, most noticeably Nautilus. The context menu comes up and then disappears. If I try again, it does the same thing. It can take several tries to get the menu to come up, and stay up, long enough for me to make a selection. This is happening on a newish Acer laptop that has had no such problem with Linux Mint or Windows 10.